trusty (3) aio_write.3posix.gz

NAME

       aio_write - asynchronous write to a file (REALTIME)

SYNOPSIS

       #include <aio.h>

       int aio_write(struct aiocb *aiocbp);

DESCRIPTION

       The  aio_write()  function  shall write aiocbp->aio_nbytes to the file associated with aiocbp->aio_fildes
       from the buffer pointed to by aiocbp->aio_buf.  The function shall return when the write request has been
       initiated or, at a minimum, queued to the file or device.

       If  prioritized  I/O  is supported for this file, then the asynchronous operation shall be submitted at a
       priority equal to the scheduling priority of the process minus aiocbp->aio_reqprio.

       The aiocbp argument may be used as an argument to aio_error() and aio_return() in order to determine  the
       error status and return status, respectively, of the asynchronous operation while it is proceeding.

       The  aiocbp  argument  points  to  an aiocb structure. If the buffer pointed to by aiocbp->aio_buf or the
       control block pointed to by aiocbp becomes an illegal address prior to asynchronous I/O completion,  then
       the behavior is undefined.

       If  O_APPEND is not set for the file descriptor aio_fildes, then the requested operation shall take place
       at the absolute position in the file as given by aio_offset, as if lseek() were called immediately  prior
       to  the  operation  with an offset equal to aio_offset and a whence equal to SEEK_SET. If O_APPEND is set
       for the file descriptor, write operations append to the file in the same order as the  calls  were  made.
       After  a  successful  call to enqueue an asynchronous I/O operation, the value of the file offset for the
       file is unspecified.

       The aiocbp->aio_lio_opcode field shall be ignored by aio_write().

       Simultaneous asynchronous operations using the same aiocbp produce undefined results.

       If synchronized I/O is enabled on the file associated  with  aiocbp->aio_fildes,  the  behavior  of  this
       function  shall  be  according  to  the  definitions  of  synchronized I/O data integrity completion, and
       synchronized I/O file integrity completion.

       For any system action that changes the process memory space while an asynchronous I/O is  outstanding  to
       the address range being changed, the result of that action is undefined.

       For  regular  files,  no  data  transfer shall occur past the offset maximum established in the open file
       description associated with aiocbp->aio_fildes.

RETURN VALUE

       The aio_write() function shall return the value zero to the calling  process  if  the  I/O  operation  is
       successfully  queued;  otherwise,  the  function  shall return the value -1 and set errno to indicate the
       error.

ERRORS

       The aio_write() function shall fail if:

       EAGAIN The requested asynchronous I/O operation was not queued due to system resource limitations.

       Each of the following conditions may be detected synchronously at the time of the call to aio_write(), or
       asynchronously.   If  any  of  the  conditions below are detected synchronously, the aio_write() function
       shall return -1 and set errno to the corresponding value. If any of the  conditions  below  are  detected
       asynchronously,  the return status of the asynchronous operation shall be set to -1, and the error status
       of the asynchronous operation is set to the corresponding value.

       EBADF  The aiocbp->aio_fildes argument is not a valid file descriptor open for writing.

       EINVAL The file offset value implied by aiocbp->aio_offset would be invalid, aiocbp->aio_reqprio is not a
              valid value, or aiocbp->aio_nbytes is an invalid value.

       In  the  case  that  the  aio_write()  successfully  queues  the  I/O operation, the return status of the
       asynchronous operation shall be one of the values normally returned by the write() function call. If  the
       operation  is  successfully  queued but is subsequently canceled or encounters an error, the error status
       for the asynchronous operation contains one of the values normally set by the write() function  call,  or
       one of the following:

       EBADF  The aiocbp->aio_fildes argument is not a valid file descriptor open for writing.

       EINVAL The file offset value implied by aiocbp->aio_offset would be invalid.

       ECANCELED
              The requested I/O was canceled before the I/O completed due to an explicit aio_cancel() request.

       The following condition may be detected synchronously or asynchronously:

       EFBIG  The  file  is  a  regular  file,  aiobcp->aio_nbytes is greater than 0, and the starting offset in
              aiobcp->aio_offset is at or beyond the offset maximum in the open file description associated with
              aiocbp->aio_fildes.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The aio_write() function is part of the Asynchronous Input and Output option and need not be available on
       all implementations.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       aio_cancel() , aio_error() ,  aio_read()  ,  aio_return()  ,  close()  ,  exec()  ,  exit()  ,  fork()  ,
       lio_listio() , lseek() , write() , the Base Definitions volume of IEEE Std 1003.1-2001, <aio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .